1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2000 Doug Rabson 5 * Copyright (c) 2004 Peter Wemm 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#include <sys/cdefs.h> 31__FBSDID("$FreeBSD$"); 32 33#include "opt_ddb.h" 34 35#include <sys/param.h> 36#include <sys/systm.h> 37#include <sys/fcntl.h> 38#include <sys/kernel.h> 39#include <sys/lock.h> 40#include <sys/malloc.h> 41#include <sys/linker.h> 42#include <sys/mutex.h> 43#include <sys/mount.h> 44#include <sys/namei.h> 45#include <sys/proc.h> 46#include <sys/rwlock.h> 47#include <sys/vnode.h> 48 49#include <machine/elf.h> 50 51#include <net/vnet.h> 52 53#include <security/mac/mac_framework.h> 54 55#include <vm/vm.h> 56#include <vm/vm_param.h> 57#include <vm/pmap.h> 58#include <vm/vm_extern.h> 59#include <vm/vm_kern.h> 60#include <vm/vm_map.h> 61#include <vm/vm_object.h> 62#include <vm/vm_page.h> 63#include <vm/vm_pager.h> 64 65#include <sys/link_elf.h> 66 67#ifdef DDB_CTF 68#include <sys/zlib.h> 69#endif 70 71#include "linker_if.h" 72 73typedef struct { 74 void *addr; 75 Elf_Off size; 76 int flags; /* Section flags. */ 77 int sec; /* Original section number. */ 78 char *name; 79} Elf_progent; 80 81typedef struct { 82 Elf_Rel *rel; 83 int nrel; 84 int sec; 85} Elf_relent; 86 87typedef struct { 88 Elf_Rela *rela; 89 int nrela; 90 int sec; 91} Elf_relaent; 92 93 94typedef struct elf_file { 95 struct linker_file lf; /* Common fields */ 96 97 int preloaded; 98 caddr_t address; /* Relocation address */ 99 vm_object_t object; /* VM object to hold file pages */ 100 Elf_Shdr *e_shdr; 101 102 Elf_progent *progtab; 103 u_int nprogtab; 104 105 Elf_relaent *relatab; 106 u_int nrelatab; 107 108 Elf_relent *reltab; 109 int nreltab; 110 111 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 112 long ddbsymcnt; /* Number of symbols */ 113 caddr_t ddbstrtab; /* String table */ 114 long ddbstrcnt; /* number of bytes in string table */ 115 116 caddr_t shstrtab; /* Section name string table */ 117 long shstrcnt; /* number of bytes in string table */ 118 119 caddr_t ctftab; /* CTF table */ 120 long ctfcnt; /* number of bytes in CTF table */ 121 caddr_t ctfoff; /* CTF offset table */ 122 caddr_t typoff; /* Type offset table */ 123 long typlen; /* Number of type entries. */ 124 125} *elf_file_t; 126 127#include <kern/kern_ctf.c> 128 129static int link_elf_link_preload(linker_class_t cls, 130 const char *, linker_file_t *); 131static int link_elf_link_preload_finish(linker_file_t); 132static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 133static int link_elf_lookup_symbol(linker_file_t, const char *, 134 c_linker_sym_t *); 135static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 136 linker_symval_t *); 137static int link_elf_search_symbol(linker_file_t, caddr_t value, 138 c_linker_sym_t *sym, long *diffp); 139 140static void link_elf_unload_file(linker_file_t); 141static int link_elf_lookup_set(linker_file_t, const char *, 142 void ***, void ***, int *); 143static int link_elf_each_function_name(linker_file_t, 144 int (*)(const char *, void *), void *); 145static int link_elf_each_function_nameval(linker_file_t, 146 linker_function_nameval_callback_t, 147 void *); 148static int link_elf_reloc_local(linker_file_t, bool); 149static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 150static long link_elf_strtab_get(linker_file_t, caddr_t *); 151 152static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 153 Elf_Addr *); 154 155static kobj_method_t link_elf_methods[] = { 156 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 157 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 158 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 159 KOBJMETHOD(linker_unload, link_elf_unload_file), 160 KOBJMETHOD(linker_load_file, link_elf_load_file), 161 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 162 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 163 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 164 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 165 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 166 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 167 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 168 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 169 KOBJMETHOD_END 170}; 171 172static struct linker_class link_elf_class = { 173#if ELF_TARG_CLASS == ELFCLASS32 174 "elf32_obj", 175#else 176 "elf64_obj", 177#endif 178 link_elf_methods, sizeof(struct elf_file) 179}; 180 181static int relocate_file(elf_file_t ef); 182static void elf_obj_cleanup_globals_cache(elf_file_t); 183 184static void 185link_elf_error(const char *filename, const char *s) 186{ 187 if (filename == NULL) 188 printf("kldload: %s\n", s); 189 else 190 printf("kldload: %s: %s\n", filename, s); 191} 192 193static void 194link_elf_init(void *arg) 195{ 196 197 linker_add_class(&link_elf_class); 198} 199 200SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 201 202static void 203link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end, 204 vm_prot_t prot) 205{ 206 int error __unused; 207 208 KASSERT(start <= end && start >= (vm_offset_t)ef->address && 209 end <= round_page((vm_offset_t)ef->address + ef->lf.size), 210 ("link_elf_protect_range: invalid range %#jx-%#jx", 211 (uintmax_t)start, (uintmax_t)end)); 212 213 if (start == end) 214 return; 215 error = vm_map_protect(kernel_map, start, end, prot, FALSE); 216 KASSERT(error == KERN_SUCCESS, 217 ("link_elf_protect_range: vm_map_protect() returned %d", error)); 218} 219 220/* 221 * Restrict permissions on linker file memory based on section flags. 222 * Sections need not be page-aligned, so overlap within a page is possible. 223 */ 224static void 225link_elf_protect(elf_file_t ef) 226{ 227 vm_offset_t end, segend, segstart, start; 228 vm_prot_t gapprot, prot, segprot; 229 int i; 230 231 /* 232 * If the file was preloaded, the last page may contain other preloaded 233 * data which may need to be writeable. ELF files are always 234 * page-aligned, but other preloaded data, such as entropy or CPU 235 * microcode may be loaded with a smaller alignment. 236 */ 237 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ; 238 239 start = end = (vm_offset_t)ef->address; 240 prot = VM_PROT_READ; 241 for (i = 0; i < ef->nprogtab; i++) { 242 /* 243 * VNET and DPCPU sections have their memory allocated by their 244 * respective subsystems. 245 */ 246 if (ef->progtab[i].name != NULL && ( 247#ifdef VIMAGE 248 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 || 249#endif 250 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0)) 251 continue; 252 253 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr); 254 segend = round_page((vm_offset_t)ef->progtab[i].addr + 255 ef->progtab[i].size); 256 segprot = VM_PROT_READ; 257 if ((ef->progtab[i].flags & SHF_WRITE) != 0) 258 segprot |= VM_PROT_WRITE; 259 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0) 260 segprot |= VM_PROT_EXECUTE; 261 262 if (end <= segstart) { 263 /* 264 * Case 1: there is no overlap between the previous 265 * segment and this one. Apply protections to the 266 * previous segment, and protect the gap between the 267 * previous and current segments, if any. 268 */ 269 link_elf_protect_range(ef, start, end, prot); 270 link_elf_protect_range(ef, end, segstart, gapprot); 271 272 start = segstart; 273 end = segend; 274 prot = segprot; 275 } else if (start < segstart && end == segend) { 276 /* 277 * Case 2: the current segment is a subrange of the 278 * previous segment. Apply protections to the 279 * non-overlapping portion of the previous segment. 280 */ 281 link_elf_protect_range(ef, start, segstart, prot); 282 283 start = segstart; 284 prot |= segprot; 285 } else if (end < segend) { 286 /* 287 * Case 3: there is partial overlap between the previous 288 * and current segments. Apply protections to the 289 * non-overlapping portion of the previous segment, and 290 * then the overlap, which must use the union of the two 291 * segments' protections. 292 */ 293 link_elf_protect_range(ef, start, segstart, prot); 294 link_elf_protect_range(ef, segstart, end, 295 prot | segprot); 296 start = end; 297 end = segend; 298 prot = segprot; 299 } else { 300 /* 301 * Case 4: the two segments reside in the same page. 302 */ 303 prot |= segprot; 304 } 305 } 306 307 /* 308 * Fix up the last unprotected segment and trailing data. 309 */ 310 link_elf_protect_range(ef, start, end, prot); 311 link_elf_protect_range(ef, end, 312 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot); 313} 314 315static int 316link_elf_link_preload(linker_class_t cls, const char *filename, 317 linker_file_t *result) 318{ 319 Elf_Ehdr *hdr; 320 Elf_Shdr *shdr; 321 Elf_Sym *es; 322 void *modptr, *baseptr, *sizeptr; 323 char *type; 324 elf_file_t ef; 325 linker_file_t lf; 326 Elf_Addr off; 327 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 328 329 /* Look to see if we have the file preloaded */ 330 modptr = preload_search_by_name(filename); 331 if (modptr == NULL) 332 return ENOENT; 333 334 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 335 baseptr = preload_search_info(modptr, MODINFO_ADDR); 336 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 337 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 338 MODINFOMD_ELFHDR); 339 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 340 MODINFOMD_SHDR); 341 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 342 " obj module") != 0 && 343 strcmp(type, "elf obj module") != 0)) { 344 return (EFTYPE); 345 } 346 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 347 shdr == NULL) 348 return (EINVAL); 349 350 lf = linker_make_file(filename, &link_elf_class); 351 if (lf == NULL) 352 return (ENOMEM); 353 354 ef = (elf_file_t)lf; 355 ef->preloaded = 1; 356 ef->address = *(caddr_t *)baseptr; 357 lf->address = *(caddr_t *)baseptr; 358 lf->size = *(size_t *)sizeptr; 359 360 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 361 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 362 hdr->e_ident[EI_VERSION] != EV_CURRENT || 363 hdr->e_version != EV_CURRENT || 364 hdr->e_type != ET_REL || 365 hdr->e_machine != ELF_TARG_MACH) { 366 error = EFTYPE; 367 goto out; 368 } 369 ef->e_shdr = shdr; 370 371 /* Scan the section header for information and table sizing. */ 372 symtabindex = -1; 373 symstrindex = -1; 374 for (i = 0; i < hdr->e_shnum; i++) { 375 switch (shdr[i].sh_type) { 376 case SHT_PROGBITS: 377 case SHT_NOBITS: 378#ifdef __amd64__ 379 case SHT_X86_64_UNWIND: 380#endif 381 /* Ignore sections not loaded by the loader. */ 382 if (shdr[i].sh_addr == 0) 383 break; 384 ef->nprogtab++; 385 break; 386 case SHT_SYMTAB: 387 symtabindex = i; 388 symstrindex = shdr[i].sh_link; 389 break; 390 case SHT_REL: 391 /* 392 * Ignore relocation tables for sections not 393 * loaded by the loader. 394 */ 395 if (shdr[shdr[i].sh_info].sh_addr == 0) 396 break; 397 ef->nreltab++; 398 break; 399 case SHT_RELA: 400 if (shdr[shdr[i].sh_info].sh_addr == 0) 401 break; 402 ef->nrelatab++; 403 break; 404 } 405 } 406 407 shstrindex = hdr->e_shstrndx; 408 if (ef->nprogtab == 0 || symstrindex < 0 || 409 symstrindex >= hdr->e_shnum || 410 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 411 shstrindex >= hdr->e_shnum || 412 shdr[shstrindex].sh_type != SHT_STRTAB) { 413 printf("%s: bad/missing section headers\n", filename); 414 error = ENOEXEC; 415 goto out; 416 } 417 418 /* Allocate space for tracking the load chunks */ 419 if (ef->nprogtab != 0) 420 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 421 M_LINKER, M_WAITOK | M_ZERO); 422 if (ef->nreltab != 0) 423 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 424 M_LINKER, M_WAITOK | M_ZERO); 425 if (ef->nrelatab != 0) 426 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 427 M_LINKER, M_WAITOK | M_ZERO); 428 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 429 (ef->nreltab != 0 && ef->reltab == NULL) || 430 (ef->nrelatab != 0 && ef->relatab == NULL)) { 431 error = ENOMEM; 432 goto out; 433 } 434 435 /* XXX, relocate the sh_addr fields saved by the loader. */ 436 off = 0; 437 for (i = 0; i < hdr->e_shnum; i++) { 438 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 439 off = shdr[i].sh_addr; 440 } 441 for (i = 0; i < hdr->e_shnum; i++) { 442 if (shdr[i].sh_addr != 0) 443 shdr[i].sh_addr = shdr[i].sh_addr - off + 444 (Elf_Addr)ef->address; 445 } 446 447 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 448 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 449 ef->ddbstrcnt = shdr[symstrindex].sh_size; 450 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 451 ef->shstrcnt = shdr[shstrindex].sh_size; 452 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 453 454 /* Now fill out progtab and the relocation tables. */ 455 pb = 0; 456 rl = 0; 457 ra = 0; 458 for (i = 0; i < hdr->e_shnum; i++) { 459 switch (shdr[i].sh_type) { 460 case SHT_PROGBITS: 461 case SHT_NOBITS: 462#ifdef __amd64__ 463 case SHT_X86_64_UNWIND: 464#endif 465 if (shdr[i].sh_addr == 0) 466 break; 467 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 468 if (shdr[i].sh_type == SHT_PROGBITS) 469 ef->progtab[pb].name = "<<PROGBITS>>"; 470#ifdef __amd64__ 471 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 472 ef->progtab[pb].name = "<<UNWIND>>"; 473#endif 474 else 475 ef->progtab[pb].name = "<<NOBITS>>"; 476 ef->progtab[pb].size = shdr[i].sh_size; 477 ef->progtab[pb].flags = shdr[i].sh_flags; 478 ef->progtab[pb].sec = i; 479 if (ef->shstrtab && shdr[i].sh_name != 0) 480 ef->progtab[pb].name = 481 ef->shstrtab + shdr[i].sh_name; 482 if (ef->progtab[pb].name != NULL && 483 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 484 void *dpcpu; 485 486 dpcpu = dpcpu_alloc(shdr[i].sh_size); 487 if (dpcpu == NULL) { 488 printf("%s: pcpu module space is out " 489 "of space; cannot allocate %#jx " 490 "for %s\n", __func__, 491 (uintmax_t)shdr[i].sh_size, 492 filename); 493 error = ENOSPC; 494 goto out; 495 } 496 memcpy(dpcpu, ef->progtab[pb].addr, 497 ef->progtab[pb].size); 498 dpcpu_copy(dpcpu, shdr[i].sh_size); 499 ef->progtab[pb].addr = dpcpu; 500#ifdef VIMAGE 501 } else if (ef->progtab[pb].name != NULL && 502 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 503 void *vnet_data; 504 505 vnet_data = vnet_data_alloc(shdr[i].sh_size); 506 if (vnet_data == NULL) { 507 printf("%s: vnet module space is out " 508 "of space; cannot allocate %#jx " 509 "for %s\n", __func__, 510 (uintmax_t)shdr[i].sh_size, 511 filename); 512 error = ENOSPC; 513 goto out; 514 } 515 memcpy(vnet_data, ef->progtab[pb].addr, 516 ef->progtab[pb].size); 517 vnet_data_copy(vnet_data, shdr[i].sh_size); 518 ef->progtab[pb].addr = vnet_data; 519#endif 520 } else if (ef->progtab[pb].name != NULL && 521 !strcmp(ef->progtab[pb].name, ".ctors")) { 522 lf->ctors_addr = ef->progtab[pb].addr; 523 lf->ctors_size = shdr[i].sh_size; 524 } 525 526 /* Update all symbol values with the offset. */ 527 for (j = 0; j < ef->ddbsymcnt; j++) { 528 es = &ef->ddbsymtab[j]; 529 if (es->st_shndx != i) 530 continue; 531 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 532 } 533 pb++; 534 break; 535 case SHT_REL: 536 if (shdr[shdr[i].sh_info].sh_addr == 0) 537 break; 538 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 539 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 540 ef->reltab[rl].sec = shdr[i].sh_info; 541 rl++; 542 break; 543 case SHT_RELA: 544 if (shdr[shdr[i].sh_info].sh_addr == 0) 545 break; 546 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 547 ef->relatab[ra].nrela = 548 shdr[i].sh_size / sizeof(Elf_Rela); 549 ef->relatab[ra].sec = shdr[i].sh_info; 550 ra++; 551 break; 552 } 553 } 554 if (pb != ef->nprogtab) { 555 printf("%s: lost progbits\n", filename); 556 error = ENOEXEC; 557 goto out; 558 } 559 if (rl != ef->nreltab) { 560 printf("%s: lost reltab\n", filename); 561 error = ENOEXEC; 562 goto out; 563 } 564 if (ra != ef->nrelatab) { 565 printf("%s: lost relatab\n", filename); 566 error = ENOEXEC; 567 goto out; 568 } 569 570 /* Local intra-module relocations */ 571 error = link_elf_reloc_local(lf, false); 572 if (error != 0) 573 goto out; 574 *result = lf; 575 return (0); 576 577out: 578 /* preload not done this way */ 579 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 580 return (error); 581} 582 583static void 584link_elf_invoke_ctors(caddr_t addr, size_t size) 585{ 586 void (**ctor)(void); 587 size_t i, cnt; 588 589 if (addr == NULL || size == 0) 590 return; 591 cnt = size / sizeof(*ctor); 592 ctor = (void *)addr; 593 for (i = 0; i < cnt; i++) { 594 if (ctor[i] != NULL) 595 (*ctor[i])(); 596 } 597} 598 599static int 600link_elf_link_preload_finish(linker_file_t lf) 601{ 602 elf_file_t ef; 603 int error; 604 605 ef = (elf_file_t)lf; 606 error = relocate_file(ef); 607 if (error) 608 return (error); 609 610 /* Notify MD code that a module is being loaded. */ 611 error = elf_cpu_load_file(lf); 612 if (error) 613 return (error); 614 615#if defined(__i386__) || defined(__amd64__) 616 /* Now ifuncs. */ 617 error = link_elf_reloc_local(lf, true); 618 if (error != 0) 619 return (error); 620#endif 621 622 /* Invoke .ctors */ 623 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 624 return (0); 625} 626 627static int 628link_elf_load_file(linker_class_t cls, const char *filename, 629 linker_file_t *result) 630{ 631 struct nameidata *nd; 632 struct thread *td = curthread; /* XXX */ 633 Elf_Ehdr *hdr; 634 Elf_Shdr *shdr; 635 Elf_Sym *es; 636 int nbytes, i, j; 637 vm_offset_t mapbase; 638 size_t mapsize; 639 int error = 0; 640 ssize_t resid; 641 int flags; 642 elf_file_t ef; 643 linker_file_t lf; 644 int symtabindex; 645 int symstrindex; 646 int shstrindex; 647 int nsym; 648 int pb, rl, ra; 649 int alignmask; 650 651 shdr = NULL; 652 lf = NULL; 653 mapsize = 0; 654 hdr = NULL; 655 656 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 657 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 658 flags = FREAD; 659 error = vn_open(nd, &flags, 0, NULL); 660 if (error) { 661 free(nd, M_TEMP); 662 return error; 663 } 664 NDFREE(nd, NDF_ONLY_PNBUF); 665 if (nd->ni_vp->v_type != VREG) { 666 error = ENOEXEC; 667 goto out; 668 } 669#ifdef MAC 670 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 671 if (error) { 672 goto out; 673 } 674#endif 675 676 /* Read the elf header from the file. */ 677 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 678 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 679 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 680 &resid, td); 681 if (error) 682 goto out; 683 if (resid != 0){ 684 error = ENOEXEC; 685 goto out; 686 } 687 688 if (!IS_ELF(*hdr)) { 689 error = ENOEXEC; 690 goto out; 691 } 692 693 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 694 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 695 link_elf_error(filename, "Unsupported file layout"); 696 error = ENOEXEC; 697 goto out; 698 } 699 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 700 || hdr->e_version != EV_CURRENT) { 701 link_elf_error(filename, "Unsupported file version"); 702 error = ENOEXEC; 703 goto out; 704 } 705 if (hdr->e_type != ET_REL) { 706 error = ENOSYS; 707 goto out; 708 } 709 if (hdr->e_machine != ELF_TARG_MACH) { 710 link_elf_error(filename, "Unsupported machine"); 711 error = ENOEXEC; 712 goto out; 713 } 714 715 lf = linker_make_file(filename, &link_elf_class); 716 if (!lf) { 717 error = ENOMEM; 718 goto out; 719 } 720 ef = (elf_file_t) lf; 721 ef->nprogtab = 0; 722 ef->e_shdr = 0; 723 ef->nreltab = 0; 724 ef->nrelatab = 0; 725 726 /* Allocate and read in the section header */ 727 nbytes = hdr->e_shnum * hdr->e_shentsize; 728 if (nbytes == 0 || hdr->e_shoff == 0 || 729 hdr->e_shentsize != sizeof(Elf_Shdr)) { 730 error = ENOEXEC; 731 goto out; 732 } 733 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 734 ef->e_shdr = shdr; 735 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 736 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 737 NOCRED, &resid, td); 738 if (error) 739 goto out; 740 if (resid) { 741 error = ENOEXEC; 742 goto out; 743 } 744 745 /* Scan the section header for information and table sizing. */ 746 nsym = 0; 747 symtabindex = -1; 748 symstrindex = -1; 749 for (i = 0; i < hdr->e_shnum; i++) { 750 if (shdr[i].sh_size == 0) 751 continue; 752 switch (shdr[i].sh_type) { 753 case SHT_PROGBITS: 754 case SHT_NOBITS: 755#ifdef __amd64__ 756 case SHT_X86_64_UNWIND: 757#endif 758 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 759 break; 760 ef->nprogtab++; 761 break; 762 case SHT_SYMTAB: 763 nsym++; 764 symtabindex = i; 765 symstrindex = shdr[i].sh_link; 766 break; 767 case SHT_REL: 768 /* 769 * Ignore relocation tables for unallocated 770 * sections. 771 */ 772 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 773 break; 774 ef->nreltab++; 775 break; 776 case SHT_RELA: 777 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 778 break; 779 ef->nrelatab++; 780 break; 781 case SHT_STRTAB: 782 break; 783 } 784 } 785 if (ef->nprogtab == 0) { 786 link_elf_error(filename, "file has no contents"); 787 error = ENOEXEC; 788 goto out; 789 } 790 if (nsym != 1) { 791 /* Only allow one symbol table for now */ 792 link_elf_error(filename, 793 "file must have exactly one symbol table"); 794 error = ENOEXEC; 795 goto out; 796 } 797 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 798 shdr[symstrindex].sh_type != SHT_STRTAB) { 799 link_elf_error(filename, "file has invalid symbol strings"); 800 error = ENOEXEC; 801 goto out; 802 } 803 804 /* Allocate space for tracking the load chunks */ 805 if (ef->nprogtab != 0) 806 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 807 M_LINKER, M_WAITOK | M_ZERO); 808 if (ef->nreltab != 0) 809 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 810 M_LINKER, M_WAITOK | M_ZERO); 811 if (ef->nrelatab != 0) 812 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 813 M_LINKER, M_WAITOK | M_ZERO); 814 815 if (symtabindex == -1) { 816 link_elf_error(filename, "lost symbol table index"); 817 error = ENOEXEC; 818 goto out; 819 } 820 /* Allocate space for and load the symbol table */ 821 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 822 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 823 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 824 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 825 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 826 &resid, td); 827 if (error) 828 goto out; 829 if (resid != 0){ 830 error = EINVAL; 831 goto out; 832 } 833 834 /* Allocate space for and load the symbol strings */ 835 ef->ddbstrcnt = shdr[symstrindex].sh_size; 836 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 837 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 838 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 839 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 840 &resid, td); 841 if (error) 842 goto out; 843 if (resid != 0){ 844 error = EINVAL; 845 goto out; 846 } 847 848 /* Do we have a string table for the section names? */ 849 shstrindex = -1; 850 if (hdr->e_shstrndx != 0 && 851 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 852 shstrindex = hdr->e_shstrndx; 853 ef->shstrcnt = shdr[shstrindex].sh_size; 854 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 855 M_WAITOK); 856 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 857 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 858 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 859 &resid, td); 860 if (error) 861 goto out; 862 if (resid != 0){ 863 error = EINVAL; 864 goto out; 865 } 866 } 867 868 /* Size up code/data(progbits) and bss(nobits). */ 869 alignmask = 0; 870 for (i = 0; i < hdr->e_shnum; i++) { 871 if (shdr[i].sh_size == 0) 872 continue; 873 switch (shdr[i].sh_type) { 874 case SHT_PROGBITS: 875 case SHT_NOBITS: 876#ifdef __amd64__ 877 case SHT_X86_64_UNWIND: 878#endif 879 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 880 break; 881 alignmask = shdr[i].sh_addralign - 1; 882 mapsize += alignmask; 883 mapsize &= ~alignmask; 884 mapsize += shdr[i].sh_size; 885 break; 886 } 887 } 888 889 /* 890 * We know how much space we need for the text/data/bss/etc. 891 * This stuff needs to be in a single chunk so that profiling etc 892 * can get the bounds and gdb can associate offsets with modules 893 */ 894 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize), 895 VM_PROT_ALL, 0, thread0.td_ucred); 896 if (ef->object == NULL) { 897 error = ENOMEM; 898 goto out; 899 } 900 901 /* 902 * In order to satisfy amd64's architectural requirements on the 903 * location of code and data in the kernel's address space, request a 904 * mapping that is above the kernel. 905 * 906 * Protections will be restricted once relocations are applied. 907 */ 908#ifdef __amd64__ 909 mapbase = KERNBASE; 910#else 911 mapbase = VM_MIN_KERNEL_ADDRESS; 912#endif 913 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 914 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 915 VM_PROT_ALL, 0); 916 if (error != KERN_SUCCESS) { 917 vm_object_deallocate(ef->object); 918 ef->object = NULL; 919 error = ENOMEM; 920 goto out; 921 } 922 923 /* Wire the pages */ 924 error = vm_map_wire(kernel_map, mapbase, 925 mapbase + round_page(mapsize), 926 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 927 if (error != KERN_SUCCESS) { 928 error = ENOMEM; 929 goto out; 930 } 931 932 /* Inform the kld system about the situation */ 933 lf->address = ef->address = (caddr_t)mapbase; 934 lf->size = mapsize; 935 936 /* 937 * Now load code/data(progbits), zero bss(nobits), allocate space for 938 * and load relocs 939 */ 940 pb = 0; 941 rl = 0; 942 ra = 0; 943 alignmask = 0; 944 for (i = 0; i < hdr->e_shnum; i++) { 945 if (shdr[i].sh_size == 0) 946 continue; 947 switch (shdr[i].sh_type) { 948 case SHT_PROGBITS: 949 case SHT_NOBITS: 950#ifdef __amd64__ 951 case SHT_X86_64_UNWIND: 952#endif 953 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 954 break; 955 alignmask = shdr[i].sh_addralign - 1; 956 mapbase += alignmask; 957 mapbase &= ~alignmask; 958 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 959 ef->progtab[pb].name = 960 ef->shstrtab + shdr[i].sh_name; 961 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 962 lf->ctors_addr = (caddr_t)mapbase; 963 lf->ctors_size = shdr[i].sh_size; 964 } 965 } else if (shdr[i].sh_type == SHT_PROGBITS) 966 ef->progtab[pb].name = "<<PROGBITS>>"; 967#ifdef __amd64__ 968 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 969 ef->progtab[pb].name = "<<UNWIND>>"; 970#endif 971 else 972 ef->progtab[pb].name = "<<NOBITS>>"; 973 if (ef->progtab[pb].name != NULL && 974 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 975 ef->progtab[pb].addr = 976 dpcpu_alloc(shdr[i].sh_size); 977 if (ef->progtab[pb].addr == NULL) { 978 printf("%s: pcpu module space is out " 979 "of space; cannot allocate %#jx " 980 "for %s\n", __func__, 981 (uintmax_t)shdr[i].sh_size, 982 filename); 983 } 984 } 985#ifdef VIMAGE 986 else if (ef->progtab[pb].name != NULL && 987 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 988 ef->progtab[pb].addr = 989 vnet_data_alloc(shdr[i].sh_size); 990 if (ef->progtab[pb].addr == NULL) { 991 printf("%s: vnet module space is out " 992 "of space; cannot allocate %#jx " 993 "for %s\n", __func__, 994 (uintmax_t)shdr[i].sh_size, 995 filename); 996 } 997 } 998#endif 999 else 1000 ef->progtab[pb].addr = 1001 (void *)(uintptr_t)mapbase; 1002 if (ef->progtab[pb].addr == NULL) { 1003 error = ENOSPC; 1004 goto out; 1005 } 1006 ef->progtab[pb].size = shdr[i].sh_size; 1007 ef->progtab[pb].flags = shdr[i].sh_flags; 1008 ef->progtab[pb].sec = i; 1009 if (shdr[i].sh_type == SHT_PROGBITS 1010#ifdef __amd64__ 1011 || shdr[i].sh_type == SHT_X86_64_UNWIND 1012#endif 1013 ) { 1014 error = vn_rdwr(UIO_READ, nd->ni_vp, 1015 ef->progtab[pb].addr, 1016 shdr[i].sh_size, shdr[i].sh_offset, 1017 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 1018 NOCRED, &resid, td); 1019 if (error) 1020 goto out; 1021 if (resid != 0){ 1022 error = EINVAL; 1023 goto out; 1024 } 1025 /* Initialize the per-cpu or vnet area. */ 1026 if (ef->progtab[pb].addr != (void *)mapbase && 1027 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 1028 dpcpu_copy(ef->progtab[pb].addr, 1029 shdr[i].sh_size); 1030#ifdef VIMAGE 1031 else if (ef->progtab[pb].addr != 1032 (void *)mapbase && 1033 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 1034 vnet_data_copy(ef->progtab[pb].addr, 1035 shdr[i].sh_size); 1036#endif 1037 } else 1038 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 1039 1040 /* Update all symbol values with the offset. */ 1041 for (j = 0; j < ef->ddbsymcnt; j++) { 1042 es = &ef->ddbsymtab[j]; 1043 if (es->st_shndx != i) 1044 continue; 1045 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 1046 } 1047 mapbase += shdr[i].sh_size; 1048 pb++; 1049 break; 1050 case SHT_REL: 1051 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1052 break; 1053 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 1054 M_WAITOK); 1055 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 1056 ef->reltab[rl].sec = shdr[i].sh_info; 1057 error = vn_rdwr(UIO_READ, nd->ni_vp, 1058 (void *)ef->reltab[rl].rel, 1059 shdr[i].sh_size, shdr[i].sh_offset, 1060 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1061 &resid, td); 1062 if (error) 1063 goto out; 1064 if (resid != 0){ 1065 error = EINVAL; 1066 goto out; 1067 } 1068 rl++; 1069 break; 1070 case SHT_RELA: 1071 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1072 break; 1073 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 1074 M_WAITOK); 1075 ef->relatab[ra].nrela = 1076 shdr[i].sh_size / sizeof(Elf_Rela); 1077 ef->relatab[ra].sec = shdr[i].sh_info; 1078 error = vn_rdwr(UIO_READ, nd->ni_vp, 1079 (void *)ef->relatab[ra].rela, 1080 shdr[i].sh_size, shdr[i].sh_offset, 1081 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1082 &resid, td); 1083 if (error) 1084 goto out; 1085 if (resid != 0){ 1086 error = EINVAL; 1087 goto out; 1088 } 1089 ra++; 1090 break; 1091 } 1092 } 1093 if (pb != ef->nprogtab) { 1094 link_elf_error(filename, "lost progbits"); 1095 error = ENOEXEC; 1096 goto out; 1097 } 1098 if (rl != ef->nreltab) { 1099 link_elf_error(filename, "lost reltab"); 1100 error = ENOEXEC; 1101 goto out; 1102 } 1103 if (ra != ef->nrelatab) { 1104 link_elf_error(filename, "lost relatab"); 1105 error = ENOEXEC; 1106 goto out; 1107 } 1108 if (mapbase != (vm_offset_t)ef->address + mapsize) { 1109 printf( 1110 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 1111 filename != NULL ? filename : "<none>", 1112 (u_long)mapbase, ef->address, (u_long)mapsize, 1113 (u_long)(vm_offset_t)ef->address + mapsize); 1114 error = ENOMEM; 1115 goto out; 1116 } 1117 1118 /* Local intra-module relocations */ 1119 error = link_elf_reloc_local(lf, false); 1120 if (error != 0) 1121 goto out; 1122 1123 /* Pull in dependencies */ 1124 VOP_UNLOCK(nd->ni_vp, 0); 1125 error = linker_load_dependencies(lf); 1126 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1127 if (error) 1128 goto out; 1129 1130 /* External relocations */ 1131 error = relocate_file(ef); 1132 if (error) 1133 goto out; 1134 1135 /* Notify MD code that a module is being loaded. */ 1136 error = elf_cpu_load_file(lf); 1137 if (error) 1138 goto out; 1139 1140#if defined(__i386__) || defined(__amd64__) 1141 /* Now ifuncs. */ 1142 error = link_elf_reloc_local(lf, true); 1143 if (error != 0) 1144 goto out; 1145#endif 1146 1147 link_elf_protect(ef); 1148 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1149 *result = lf; 1150 1151out: 1152 VOP_UNLOCK(nd->ni_vp, 0); 1153 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1154 free(nd, M_TEMP); 1155 if (error && lf) 1156 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1157 free(hdr, M_LINKER); 1158 1159 return error; 1160} 1161 1162static void 1163link_elf_unload_file(linker_file_t file) 1164{ 1165 elf_file_t ef = (elf_file_t) file; 1166 u_int i; 1167 1168 /* Notify MD code that a module is being unloaded. */ 1169 elf_cpu_unload_file(file); 1170 1171 if (ef->progtab) { 1172 for (i = 0; i < ef->nprogtab; i++) { 1173 if (ef->progtab[i].size == 0) 1174 continue; 1175 if (ef->progtab[i].name == NULL) 1176 continue; 1177 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1178 dpcpu_free(ef->progtab[i].addr, 1179 ef->progtab[i].size); 1180#ifdef VIMAGE 1181 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1182 vnet_data_free(ef->progtab[i].addr, 1183 ef->progtab[i].size); 1184#endif 1185 } 1186 } 1187 if (ef->preloaded) { 1188 free(ef->reltab, M_LINKER); 1189 free(ef->relatab, M_LINKER); 1190 free(ef->progtab, M_LINKER); 1191 free(ef->ctftab, M_LINKER); 1192 free(ef->ctfoff, M_LINKER); 1193 free(ef->typoff, M_LINKER); 1194 if (file->pathname != NULL) 1195 preload_delete_name(file->pathname); 1196 return; 1197 } 1198 1199 for (i = 0; i < ef->nreltab; i++) 1200 free(ef->reltab[i].rel, M_LINKER); 1201 for (i = 0; i < ef->nrelatab; i++) 1202 free(ef->relatab[i].rela, M_LINKER); 1203 free(ef->reltab, M_LINKER); 1204 free(ef->relatab, M_LINKER); 1205 free(ef->progtab, M_LINKER); 1206 1207 if (ef->object != NULL) 1208 vm_map_remove(kernel_map, (vm_offset_t)ef->address, 1209 (vm_offset_t)ef->address + ptoa(ef->object->size)); 1210 free(ef->e_shdr, M_LINKER); 1211 free(ef->ddbsymtab, M_LINKER); 1212 free(ef->ddbstrtab, M_LINKER); 1213 free(ef->shstrtab, M_LINKER); 1214 free(ef->ctftab, M_LINKER); 1215 free(ef->ctfoff, M_LINKER); 1216 free(ef->typoff, M_LINKER); 1217} 1218 1219static const char * 1220symbol_name(elf_file_t ef, Elf_Size r_info) 1221{ 1222 const Elf_Sym *ref; 1223 1224 if (ELF_R_SYM(r_info)) { 1225 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1226 return ef->ddbstrtab + ref->st_name; 1227 } else 1228 return NULL; 1229} 1230 1231static Elf_Addr 1232findbase(elf_file_t ef, int sec) 1233{ 1234 int i; 1235 Elf_Addr base = 0; 1236 1237 for (i = 0; i < ef->nprogtab; i++) { 1238 if (sec == ef->progtab[i].sec) { 1239 base = (Elf_Addr)ef->progtab[i].addr; 1240 break; 1241 } 1242 } 1243 return base; 1244} 1245 1246static int 1247relocate_file(elf_file_t ef) 1248{ 1249 const Elf_Rel *rellim; 1250 const Elf_Rel *rel; 1251 const Elf_Rela *relalim; 1252 const Elf_Rela *rela; 1253 const char *symname; 1254 const Elf_Sym *sym; 1255 int i; 1256 Elf_Size symidx; 1257 Elf_Addr base; 1258 1259 1260 /* Perform relocations without addend if there are any: */ 1261 for (i = 0; i < ef->nreltab; i++) { 1262 rel = ef->reltab[i].rel; 1263 if (rel == NULL) { 1264 link_elf_error(ef->lf.filename, "lost a reltab!"); 1265 return (ENOEXEC); 1266 } 1267 rellim = rel + ef->reltab[i].nrel; 1268 base = findbase(ef, ef->reltab[i].sec); 1269 if (base == 0) { 1270 link_elf_error(ef->lf.filename, "lost base for reltab"); 1271 return (ENOEXEC); 1272 } 1273 for ( ; rel < rellim; rel++) { 1274 symidx = ELF_R_SYM(rel->r_info); 1275 if (symidx >= ef->ddbsymcnt) 1276 continue; 1277 sym = ef->ddbsymtab + symidx; 1278 /* Local relocs are already done */ 1279 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1280 continue; 1281 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1282 elf_obj_lookup)) { 1283 symname = symbol_name(ef, rel->r_info); 1284 printf("link_elf_obj: symbol %s undefined\n", 1285 symname); 1286 return (ENOENT); 1287 } 1288 } 1289 } 1290 1291 /* Perform relocations with addend if there are any: */ 1292 for (i = 0; i < ef->nrelatab; i++) { 1293 rela = ef->relatab[i].rela; 1294 if (rela == NULL) { 1295 link_elf_error(ef->lf.filename, "lost a relatab!"); 1296 return (ENOEXEC); 1297 } 1298 relalim = rela + ef->relatab[i].nrela; 1299 base = findbase(ef, ef->relatab[i].sec); 1300 if (base == 0) { 1301 link_elf_error(ef->lf.filename, 1302 "lost base for relatab"); 1303 return (ENOEXEC); 1304 } 1305 for ( ; rela < relalim; rela++) { 1306 symidx = ELF_R_SYM(rela->r_info); 1307 if (symidx >= ef->ddbsymcnt) 1308 continue; 1309 sym = ef->ddbsymtab + symidx; 1310 /* Local relocs are already done */ 1311 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1312 continue; 1313 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1314 elf_obj_lookup)) { 1315 symname = symbol_name(ef, rela->r_info); 1316 printf("link_elf_obj: symbol %s undefined\n", 1317 symname); 1318 return (ENOENT); 1319 } 1320 } 1321 } 1322 1323 /* 1324 * Only clean SHN_FBSD_CACHED for successful return. If we 1325 * modified symbol table for the object but found an 1326 * unresolved symbol, there is no reason to roll back. 1327 */ 1328 elf_obj_cleanup_globals_cache(ef); 1329 1330 return (0); 1331} 1332 1333static int 1334link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1335{ 1336 elf_file_t ef = (elf_file_t) lf; 1337 const Elf_Sym *symp; 1338 const char *strp; 1339 int i; 1340 1341 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1342 strp = ef->ddbstrtab + symp->st_name; 1343 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1344 *sym = (c_linker_sym_t) symp; 1345 return 0; 1346 } 1347 } 1348 return ENOENT; 1349} 1350 1351static int 1352link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1353 linker_symval_t *symval) 1354{ 1355 elf_file_t ef; 1356 const Elf_Sym *es; 1357 caddr_t val; 1358 1359 ef = (elf_file_t) lf; 1360 es = (const Elf_Sym*) sym; 1361 val = (caddr_t)es->st_value; 1362 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1363 symval->name = ef->ddbstrtab + es->st_name; 1364 val = (caddr_t)es->st_value; 1365 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1366 val = ((caddr_t (*)(void))val)(); 1367 symval->value = val; 1368 symval->size = es->st_size; 1369 return 0; 1370 } 1371 return ENOENT; 1372} 1373 1374static int 1375link_elf_search_symbol(linker_file_t lf, caddr_t value, 1376 c_linker_sym_t *sym, long *diffp) 1377{ 1378 elf_file_t ef = (elf_file_t) lf; 1379 u_long off = (uintptr_t) (void *) value; 1380 u_long diff = off; 1381 u_long st_value; 1382 const Elf_Sym *es; 1383 const Elf_Sym *best = NULL; 1384 int i; 1385 1386 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1387 if (es->st_name == 0) 1388 continue; 1389 st_value = es->st_value; 1390 if (off >= st_value) { 1391 if (off - st_value < diff) { 1392 diff = off - st_value; 1393 best = es; 1394 if (diff == 0) 1395 break; 1396 } else if (off - st_value == diff) { 1397 best = es; 1398 } 1399 } 1400 } 1401 if (best == NULL) 1402 *diffp = off; 1403 else 1404 *diffp = diff; 1405 *sym = (c_linker_sym_t) best; 1406 1407 return 0; 1408} 1409 1410/* 1411 * Look up a linker set on an ELF system. 1412 */ 1413static int 1414link_elf_lookup_set(linker_file_t lf, const char *name, 1415 void ***startp, void ***stopp, int *countp) 1416{ 1417 elf_file_t ef = (elf_file_t)lf; 1418 void **start, **stop; 1419 int i, count; 1420 1421 /* Relative to section number */ 1422 for (i = 0; i < ef->nprogtab; i++) { 1423 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1424 strcmp(ef->progtab[i].name + 4, name) == 0) { 1425 start = (void **)ef->progtab[i].addr; 1426 stop = (void **)((char *)ef->progtab[i].addr + 1427 ef->progtab[i].size); 1428 count = stop - start; 1429 if (startp) 1430 *startp = start; 1431 if (stopp) 1432 *stopp = stop; 1433 if (countp) 1434 *countp = count; 1435 return (0); 1436 } 1437 } 1438 return (ESRCH); 1439} 1440 1441static int 1442link_elf_each_function_name(linker_file_t file, 1443 int (*callback)(const char *, void *), void *opaque) 1444{ 1445 elf_file_t ef = (elf_file_t)file; 1446 const Elf_Sym *symp; 1447 int i, error; 1448 1449 /* Exhaustive search */ 1450 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1451 if (symp->st_value != 0 && 1452 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1453 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1454 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1455 if (error) 1456 return (error); 1457 } 1458 } 1459 return (0); 1460} 1461 1462static int 1463link_elf_each_function_nameval(linker_file_t file, 1464 linker_function_nameval_callback_t callback, void *opaque) 1465{ 1466 linker_symval_t symval; 1467 elf_file_t ef = (elf_file_t)file; 1468 const Elf_Sym* symp; 1469 int i, error; 1470 1471 /* Exhaustive search */ 1472 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1473 if (symp->st_value != 0 && 1474 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1475 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1476 error = link_elf_symbol_values(file, 1477 (c_linker_sym_t)symp, &symval); 1478 if (error) 1479 return (error); 1480 error = callback(file, i, &symval, opaque); 1481 if (error) 1482 return (error); 1483 } 1484 } 1485 return (0); 1486} 1487 1488static void 1489elf_obj_cleanup_globals_cache(elf_file_t ef) 1490{ 1491 Elf_Sym *sym; 1492 Elf_Size i; 1493 1494 for (i = 0; i < ef->ddbsymcnt; i++) { 1495 sym = ef->ddbsymtab + i; 1496 if (sym->st_shndx == SHN_FBSD_CACHED) { 1497 sym->st_shndx = SHN_UNDEF; 1498 sym->st_value = 0; 1499 } 1500 } 1501} 1502 1503/* 1504 * Symbol lookup function that can be used when the symbol index is known (ie 1505 * in relocations). It uses the symbol index instead of doing a fully fledged 1506 * hash table based lookup when such is valid. For example for local symbols. 1507 * This is not only more efficient, it's also more correct. It's not always 1508 * the case that the symbol can be found through the hash table. 1509 */ 1510static int 1511elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1512{ 1513 elf_file_t ef = (elf_file_t)lf; 1514 Elf_Sym *sym; 1515 const char *symbol; 1516 Elf_Addr res1; 1517 1518 /* Don't even try to lookup the symbol if the index is bogus. */ 1519 if (symidx >= ef->ddbsymcnt) { 1520 *res = 0; 1521 return (EINVAL); 1522 } 1523 1524 sym = ef->ddbsymtab + symidx; 1525 1526 /* Quick answer if there is a definition included. */ 1527 if (sym->st_shndx != SHN_UNDEF) { 1528 res1 = (Elf_Addr)sym->st_value; 1529 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1530 res1 = ((Elf_Addr (*)(void))res1)(); 1531 *res = res1; 1532 return (0); 1533 } 1534 1535 /* If we get here, then it is undefined and needs a lookup. */ 1536 switch (ELF_ST_BIND(sym->st_info)) { 1537 case STB_LOCAL: 1538 /* Local, but undefined? huh? */ 1539 *res = 0; 1540 return (EINVAL); 1541 1542 case STB_GLOBAL: 1543 case STB_WEAK: 1544 /* Relative to Data or Function name */ 1545 symbol = ef->ddbstrtab + sym->st_name; 1546 1547 /* Force a lookup failure if the symbol name is bogus. */ 1548 if (*symbol == 0) { 1549 *res = 0; 1550 return (EINVAL); 1551 } 1552 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1553 1554 /* 1555 * Cache global lookups during module relocation. The failure 1556 * case is particularly expensive for callers, who must scan 1557 * through the entire globals table doing strcmp(). Cache to 1558 * avoid doing such work repeatedly. 1559 * 1560 * After relocation is complete, undefined globals will be 1561 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1562 * above. 1563 */ 1564 if (res1 != 0) { 1565 sym->st_shndx = SHN_FBSD_CACHED; 1566 sym->st_value = res1; 1567 *res = res1; 1568 return (0); 1569 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1570 sym->st_value = 0; 1571 *res = 0; 1572 return (0); 1573 } 1574 return (EINVAL); 1575 1576 default: 1577 return (EINVAL); 1578 } 1579} 1580 1581static void 1582link_elf_fix_link_set(elf_file_t ef) 1583{ 1584 static const char startn[] = "__start_"; 1585 static const char stopn[] = "__stop_"; 1586 Elf_Sym *sym; 1587 const char *sym_name, *linkset_name; 1588 Elf_Addr startp, stopp; 1589 Elf_Size symidx; 1590 int start, i; 1591 1592 startp = stopp = 0; 1593 for (symidx = 1 /* zero entry is special */; 1594 symidx < ef->ddbsymcnt; symidx++) { 1595 sym = ef->ddbsymtab + symidx; 1596 if (sym->st_shndx != SHN_UNDEF) 1597 continue; 1598 1599 sym_name = ef->ddbstrtab + sym->st_name; 1600 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1601 start = 1; 1602 linkset_name = sym_name + sizeof(startn) - 1; 1603 } 1604 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1605 start = 0; 1606 linkset_name = sym_name + sizeof(stopn) - 1; 1607 } 1608 else 1609 continue; 1610 1611 for (i = 0; i < ef->nprogtab; i++) { 1612 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1613 startp = (Elf_Addr)ef->progtab[i].addr; 1614 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1615 break; 1616 } 1617 } 1618 if (i == ef->nprogtab) 1619 continue; 1620 1621 sym->st_value = start ? startp : stopp; 1622 sym->st_shndx = i; 1623 } 1624} 1625 1626static int 1627link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1628{ 1629 elf_file_t ef = (elf_file_t)lf; 1630 const Elf_Rel *rellim; 1631 const Elf_Rel *rel; 1632 const Elf_Rela *relalim; 1633 const Elf_Rela *rela; 1634 const Elf_Sym *sym; 1635 Elf_Addr base; 1636 int i; 1637 Elf_Size symidx; 1638 1639 link_elf_fix_link_set(ef); 1640 1641 /* Perform relocations without addend if there are any: */ 1642 for (i = 0; i < ef->nreltab; i++) { 1643 rel = ef->reltab[i].rel; 1644 if (rel == NULL) { 1645 link_elf_error(ef->lf.filename, "lost a reltab"); 1646 return (ENOEXEC); 1647 } 1648 rellim = rel + ef->reltab[i].nrel; 1649 base = findbase(ef, ef->reltab[i].sec); 1650 if (base == 0) { 1651 link_elf_error(ef->lf.filename, "lost base for reltab"); 1652 return (ENOEXEC); 1653 } 1654 for ( ; rel < rellim; rel++) { 1655 symidx = ELF_R_SYM(rel->r_info); 1656 if (symidx >= ef->ddbsymcnt) 1657 continue; 1658 sym = ef->ddbsymtab + symidx; 1659 /* Only do local relocs */ 1660 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1661 continue; 1662 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1663 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1664 continue; 1665 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1666 elf_obj_lookup) != 0) 1667 return (ENOEXEC); 1668 } 1669 } 1670 1671 /* Perform relocations with addend if there are any: */ 1672 for (i = 0; i < ef->nrelatab; i++) { 1673 rela = ef->relatab[i].rela; 1674 if (rela == NULL) { 1675 link_elf_error(ef->lf.filename, "lost a relatab!"); 1676 return (ENOEXEC); 1677 } 1678 relalim = rela + ef->relatab[i].nrela; 1679 base = findbase(ef, ef->relatab[i].sec); 1680 if (base == 0) { 1681 link_elf_error(ef->lf.filename, "lost base for reltab"); 1682 return (ENOEXEC); 1683 } 1684 for ( ; rela < relalim; rela++) { 1685 symidx = ELF_R_SYM(rela->r_info); 1686 if (symidx >= ef->ddbsymcnt) 1687 continue; 1688 sym = ef->ddbsymtab + symidx; 1689 /* Only do local relocs */ 1690 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1691 continue; 1692 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1693 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1694 continue; 1695 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1696 elf_obj_lookup) != 0) 1697 return (ENOEXEC); 1698 } 1699 } 1700 return (0); 1701} 1702 1703static long 1704link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1705{ 1706 elf_file_t ef = (elf_file_t)lf; 1707 1708 *symtab = ef->ddbsymtab; 1709 1710 if (*symtab == NULL) 1711 return (0); 1712 1713 return (ef->ddbsymcnt); 1714} 1715 1716static long 1717link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1718{ 1719 elf_file_t ef = (elf_file_t)lf; 1720 1721 *strtab = ef->ddbstrtab; 1722 1723 if (*strtab == NULL) 1724 return (0); 1725 1726 return (ef->ddbstrcnt); 1727} 1728